Fuel metering valve for internal combustion engines



r 3 l ,E S n w a :.w m 1+ 5./ 3 y WW n S v Y a 2 W p m ,u M... I 3 m e .ma Am M mm I. 8 6 Z N 2 dl. I 9 if@ .8 Y. Q M S :l .,...2 4. u@ m 5 ru w m 4 L M ,m 1 4 E Al m 4 ma 1f) 4 w ...w m w o w\ 1 M Q mi (.w m H 1 n Us f//Z F. m. f// m 7 ,2 m 4 k M June 13, 1967 Flled June 25, 1964 l.. PERAS June 13, 1967 FUEL METERING VALVE FOR INTERNAL COMBUSTION ENGINES Filed June 25, 1964 2 Sheets-Sheet 2 United States Patent O FUEL METERING VALVE FOR INTERNAL COMBUSTION ENGINES Lucien Pras, Billancourt, France, assignor to Regie Nationale des Usines Renault, Billancourt, France Filed June 25, 1964, Ser. No. 377,932

Claims priority, application France, Aug. 27, 1963,

945,803, Patent 1,374,495 3 Claims. (Cl. 261-71) This invention relates to a fuel metering valve for in- -ternal combustion engines and is more specifically concerned with improvements to the gas and liquid metering and emulsifying slide-valve system which was the subject of Patent No. 3,003,755, tiled by the applicant, of Oct. 10, 1961, which had for its object to do away with the needle systems customarily used for the same purpose.

In the above-cited patent, the moving slide-valve, in

Vthe course of its translation, masked more or less the calibrated fuel orifice and received the fuel in a conical chamber into which atmospheric air was continuously supplied, and nally delivered the mixture from the cone outlet into t'he engine inlet manifold. The application of -the slide-valve against its port-face was also disclosed.

The object of this was to limit the contact pressure of the slide-valve to the values strictly ladequate for efiicient operation in order to limit friction to a minimum. The translation of this slide-valve was generally effected in non-positive manner, as disclosed for example in Patent No. 3,132,193, filed by the applicant, of May 5, 1964.

`Since the position of the slide-valve resulted from a state of forces in equilibrium, it was manifest that its friction had to be reduced to a minimum.

Experience showed that this slide-valve was capable of very accurate flow regulation for a given fuel pressure at its calibrated orice; on the other hand, it became ap- `parent that the translation means of the slide-valve, and

more generally the metering system utilized, did not take full cognizance of engine operating conditions.

The present invention has for its object to provide a slide-valve of this type in which a different method of ensuring mutual contact in conjunction with positive translation control means is utilized.

As in the case of the Patents 3,003,755 and 3,132,193

`cited hereinabove, a valve according to this invention may `strength and is translated by a screw against a countering return spring which is required to enable it to invariably overcome the friction predetermined by the thrust spring and continuously maintain the block in contact with the control screw. The fuel is fed into the stationary block, re-enters the movable block through facing orifices which are always open notwithstanding slide-valve motion, and debouches through the calibrated orifice which is more or less masked by the stationary block.

Since there may be disadvantages in causing the fuel to flow through the supporting element of the stationary block, which is subjected to higher temperatures through its bearing against engine Acomponents which transmit heat to it by conduction, it may be preferable to introduce the fuel directly into the movable block in order to keep it free from contact with hot parts for as long as possible and thus avoid unwanted vaporization, and this, precisely, is a further feature of the present invention.

Still another feature resides in the fact that said control screw is tted into said supporting element in conjunction with the use of a counter nut which also screws into said element with a slightly different thread pitch, whereby the position of the slide-valve can be precisely adjusted by rotating said counter nut:

Yet another feature of the invention resides in the possibility of suddenly shifting the slide-valve in order to fully mask the calibrated orifice and thus completely cut off the fuel supply, by means of a lever which operates on the slide-valve on the same side as said control screw and independently thereof through separate actuating means. When this lever is retracted the slide-valve is repositioned precisely against the screw, and the calibrated orifice reverts to the exact degree of aperture it possessed before the high-speed masking operation.

Since it is not always necessary to preserve the calibrated orifice from the influence of the negative pressure prevailing in the inlet tract, one specific constructional form of the present invention dispenses with a secondary air orifice.

The various features hereinbefore disclosed can be combined in various ways without departing from the scope of the invention.

Two exemplary constructional forms of the subject valve of this invention will now bedescribed with reference to the accompanying drawings, in which:

FIGURE 1 shows in longitudinal section through the line I-I of FIGURE 2 a valve having fuel inlet means passing through the stationary block and also atmospheric pressure air inlet means, but which is devoid of ne adjustment `and high-speed closure means;

FIGURE 2 shows the same valve in cross-section through the line II-II of FIGURE 1;

FIGURE 3 shows in longitudinal section through the line III- III of FIGURE 4 a valve having a direct fuel intake to the movable block through a flexible line but no air inlet means, but having a fine adjustment counter nut and high-speed means; i

FIGURE 4 shows the same valve in crosssection through the line IV-IV of FIGURE 3;

FIGURE 5 shows the same valve in fragmental plan view, with particular reference to the high-speed closure system, and

FIGURE 6 is a cross-sectional view similar to FIG- URE 4, showing lan lalternative flexible fuel supply system.

Referring first to FIGS. 1 and 2, there is shown thereon an internal combustion engine inlet tube 1 which may be located just past the throttle and ahead of the branching of the inlet pipes or which may be one of the inlet pipes leading from the inlet manifold to each cylinder. In the former case, it supplies all the cylinder-s, in the latter case only one cylinder. To said pipe is secured by means of screws (not shown) a block 2, a plate 3 and a block 4, these three parts being rigidly interconnected by the same screws or by other screws (likewise not shown). Gaskets 5 and 6 ensure leak-tightness between these parts. The upper surface 7 of the block 2 is rigorously flat and forms a port-face. Against this portface is applied a movable slide-valve 8 whose lower fiat and polished face provides a flat joint sliding over the face 7. The slidevalve 8 is applied against the face 7 by a spring 9` bearing upon a cup 10l secured into the block 4, leaktightness being provided by a sealing washer 11. The spring 9 has its two ends correctly centered in the valve 8 and in the upper cup 10, respectively, but is unrestrained over the remainder of its length. By virtue of this freedom and of its length, said spring will accommodate a slight displacement of the slide-valve of the order of l mm. without jamming or substantially changing the orientation of its thrust. The slide-valve is rectangular in shape and passes through a groove 12 in the plate 3, and this plate acts as a slideway. Adjusted to have very slight sideway clearance (FIGURE 2), the slide-valve can lmove longitudinally over a short distance (FIGURE l) while remaining applied against its port-face 7 by its spring 9. This movement is controlled by a precision screw 13 against a countering return spring 14 which bears against an adjustable plug 15. The strength of the spring 14 is so adjusted that it invariably overcome the friction of the slidevalve 8 against its port-face and always apply said slidevalve against the screw 13.

The fuel enters through a union 16 into the block 4 and Y flows through the passages 17 formed in the block 4, 18 in the plate 3 and 19 in the block 2. The passage 19 communicates through the port-face with the angled passage 20 formed in the slide-valve and then with the calibrated jet 21 which opens out onto the port-face 7, and this jet is partly masked by the surface of the portface and partly uncovered by a conical hole 22, that portion of the directrix of the larger base of said hole which is located on the right of FIGURE 1 bonding the uncovered part of the jet. The residual section allows -a certain amount of fuel to flow into the cone 22 and, through the orifice 23 forming the smaller base thereof, into the pipe 1.

Previously filtered air at atmospheric pressure enters the valve through the union 24 and fills the interior theref completely, it also penetrates into the conical hole 22 through the cutaway 25.

Operation is a-s follows: for a given position of the valve 8 and a given negative pressure in the pipe l-these valves being usually interlinked-fuel under pressure flows through the passage 16, `17 18, 19 and then through the passage (there being always a common section Ibetween the passages 19 and 20 no matter what the position of the valve may be), and ultimately spurts through the remaining uncovered section of the jet 21 into the emulsifying cone 22, the air being invariably at atmospheric pressure within the cone 22 because the orifice 23 is chosen sufficiently small. The greater the depression in the pipe 1, the stronger the air stream flowing into the cone 22, whereby an air-fuel emulsion is created in the cone 22 which is delivered into the pipe 1 through the orifice 23.

The fact of the slide-Valve being fluid-tightly applied against the port-face obviates any short circuit between the outlets -of the holes 20 and 21 upon said port face.

When the screw 13 is rotated it translates and moves the slide-valve (against the invariably countering urge of spring 14) in one direction or the other. Since the marginal edge of the base of cone 22 is fixed, the passageway section is thereby modified and, for a given fuel pressure, the fuel flow rate is consequently modified in the desired sense, atmospheric pressure invariably prevailing in the cone 22 even if the depression created in the pipe has varied; in this latter event, the secondary air flow admitted through 25 will vary and, with it, the emulsion proportion.

Reference is now had to FIGURES 3, 4 and 5 for an alternative preferred constructional form of the subject valve of this invention for cases where the introduction of secondary air is not necessary but where it may be feared that the various passages formed in the metal blocks may be at too high a temperature and cause fuel evaporation.

Against the pipe 1 as hereinbefore defined is applied a block 26 by means of screws 27, duid-tightness being ensured by a seal 28. Within a circular groove 29 of the block 29 of the block 26 is located a block of revolution 30 which is clamped in position with its seal 31 by a nut 32. The block 30 has formed therein a cylindrical hole 33 of fairly large diameter provided with a fillet at the top bounded by a circle of smaller diameter than that of the hole 34. The hole 34 formed thus opens onto the portface formed by the upper flat surface 35 of the block 30.

Onto the block 30 is applied the lower fiat and polished face of a solid rectangular slide-valve 36. The latter has extending through its centre a calibrated jet 37 which is partly masked by the fillet 34 and which is fed through a duct 38 of larger section. Said slide-valve is applied against block 30 by a spring 39 of which one end is centered upon a portion of the block 36 and the other in a cap 40 secured to a plate 41 by screws 42. The plate 41 is fixed to the block 26 by screws 43. The block 36 is a sliding fit between two extensions 44 of the cap 40 which allow it to move only longitudinally. These extensions 44 likewise serve, through liats 45, in the block 30, to secure the latter in position in the desired orientation while the nut 32 is being tightened.

Longitudinal motion of block 36 is controlled by a precision screw 46 against a return spring 47 which is adjusted by a plug 48 and functions as in the constructional form described precedingly. The screw 46 is operated by a cranked lever 49 secured by a nut S0. The screw 46 is not screwed directly into the block 26 but into a second tubular dual-pitch screw 51 the inner and outer threads of which are cut in the same sense and have slightly different pitches.

The fuel enters the passage 52 drilled through a stub 53 on the cap 40. An external flexible fuel feed line is tted over said stub. Inside the valve, a exible plastic tube 54 has one end forced into the cap duct 52 and the other end into the valve duct 38 and thus conveys the fuel to the calibrated hole 37.

A lever 55 is arranged to bear against the same slidevalve face as the screw. This lever passes beneath the smooth extremity of the screw 46 and can be swivelled about a vertical pin 56 whose lower end is pivotally mounted in the block 26 and the upper bearing in the plate 41. An actuating lever 57 operates the lever 55.

The device hereinbefore described functions in the following manner: for a given slide-valve position determined by the screw 46 and its return Vspring 47, the orifice 37 is partly masked by the iillet 34, thus establishing a determinate value of the passageway section. The fuel admitted under a certain pressure through the stub 53 reaches the passage 38 and the jet 37 without any leakage taking place. The three factors determining the fiow rate are the jet section uncovered, the fuel pressure above the jet and the depression created in the pipe below said jet, and these three factors jointly result in a specified air flow rate through the pipe 1. The function of the valve is confined to varying the passageway section. Rotation of the lever 49 in one direction or the other varies the section in the required sense, but only provided that the valve be maintained in contact with the port-face. This is achieved by the springs 39 and 47, by virtue of the flexibility of the tube 54 and the short permissible travel distance (less than 1 mm.).

In order to set an initial value for said section and, in particular, make equal the initial values for different valves with mutually coupled levers 49, it will suiiice to rotate the tubular screw 51 while the lever 49 remains stationary. Since the screw threads of identical sense operate differentially, the screw 46 and hence the valve 36 will move longitudinally through a small distance for a correspondingly fairly ample rotation of the counter nut 51, thus providing adjustment of great sensitivity.

When it is desired at any given moment to completely cut off the fuel supply, the lever 57 must be moved to the left. Through the medium of the pin 56, the lever 55 bears against the valve 36, which is thereby caused to recede from contact with the screw 46 and to compress the spring 47. The magnitude of the force to be applied to the lever 57 must evidently be greater than the magnitude corresponding to the initial tension of the spring 47. The orifice 37 is then completely masked by the port-face and no ow takes place. When it is desired to turn on the fuel supply once more, the lever 57 must be released abruptly. The spring 4'7 returns the valve into contact with the screw 46 and into the initial adjustment conditions, or into such adjustment conditions as may have been established during the time of fuel cut-oir, which resulted in a slight rotation of the lever 49, a change in the fuel supply pressure, or a change in the depression created in the inlet pipe.

A noteworthy feature is that by removing the cap 40 and undoing the two screws 42, the spring 39, the tube 54 and the slide-valve 36 can be withdrawn without in any way modifying the adjustment of the screw 46 or the lever S5. Should it be necessary to loosen the screw 48 to some extent, all that is necessary is to retighten it by the same amount when reassembling. This screw, however, defines a force, not a position of the slide-valve, so that the valve, port-face and jet can be cleaned if necessary without touching the slow or fast liow rate adjustment, which is a feature greatly appreciated by motor repairers, for instance.

Lastly, reference is had to FIGURE 6 for an alternative method of supplying the fuel: a stub 58 is fixed directly onto the slide-valve 36 and the external exible line 59 is fitted directly onto this stub. In this `constructional form, the cap 60 is slightly higher than in the previous example described and is provided with a fuel line guiding washer 61 designed to isolate the slide-valve from possible movements of the line 59.

What is claimed is:

1. A fuel metering device mounted on the inlet pipe -of an internal combustion engine at a point enabling it to supply at least a single cylinder thereof; said device comprising a rectangular slide-valve having a calibrated circular jet supplied with fuel; a stationary block having a port face disposed between said slide-valve and said inlet pipe and defining an oriiice in communication with said pipe; the marginal edge of said orifice masking at least a portion of Isaid jet; means urging said slide-valve against said port face; means to adjust the position of said slide-valve with respect to said orifice to regulate fuel flow to said pipe, and a flexible tube extending through said slide-valve to said delivery jet and Iadapted to supply said slide-valve with fuel, means to fully preserve the fluid tightness of said slide-valve against its associated portface during its slight displacement while at the same time preventing any excess heat liable to partly vaporize the fuel from being transmitted to the fuel supply line.

2. A fuel metering device mounted on the inlet pipe of an internal combustion engine at a point enabling it to supply Iat least a single cylinder thereof; said device comprising a rectangular slide-valve having a calibrated circular jet supplied with fuel; a stationary block having a port-face disposed between said slide-valve and said inlet pipe and defining an orifice in communication with said pipe; the marginal edge of said orice masking at least a portion of said jet; means urging said slide-Valve against said port-face; and adjustable precision screw acting upon a lateral face of said slide-valve to adjust the position of said slide-valve with respect to said orifice to regulate fuel flow to said pipe; a countering return spring acting on the opposite face of said slide-valve; and a tubular initial adjustment screw into which said precision screw screws, the respective internal and external screw threads of said screws being cut in the same sense, but at slightly diiferent pitches.

3. The device of claim 2, further comprising a highspeed motion lever disposed adjacent said slide-valve on the same side thereof as said precision screw, said lever being adapted to engage said slide-valve to adjust the p0- sition of said slide-valve with respect -to said orifice independent of the position of said screws.

References Cited UNITED STATES PATENTS 968,215 8/1910 Westaway 261--50 3,003,755 10/1961 Peras 26l71 HARRY B. THORNTON, Primary Examiner.

RONALD R. WEAVER, Examiner. 

1. A FUEL METERING DEVICE MOUNTED ON THE INLET PIPE OF AN INTERNAL COMBUSTION ENGINE AT A POINT ENABLING IT TO SUPPLY AT LEAST A SINGLE CYLINDER THEREOF; SAID DEVICE COMPRISING A RECTANGULAR SLIDE-VALVE HAVING A CALIBRATED CIRCULAR JET SUPPLIED WITH FUEL; A STATIONARY BLOCK HAVING A PORT FACE DISPOSED BETWEEN SAID SLIDE-WAY AND SAID INLET PIPE AND DEFINING AN ORIFICE IN COMMUNICATION WITH SAID PIPE; THE MARGINAL EDGE OF SAID ORIFICE MASKING AT LEAST A PORTION OF SAID JET; MEANS URGING SAID SLIDE-VALVE AGAINST SAID PORT FACE; MEANS TO ADJUST THE POSITION OF SAID SLIDE-VALVE WITH RESPECT TO SAID ORIFICE TO REGULATE FUEL FLOW TO SAID PIPE, AND A FLEXIBLE TUBE EXTENDING THROUGH SAID SLIDE-VALVE TO SAID DELIVERY JET AND ADAPTED TO SUPPLY MEANS ASSOCIATED WITH SAID GAS DISCHARGE OPENING FOR MAINTIGHTNESS OF SAID SLIDE-VALVE AGAINST ITS ASSOCIATED PORTFACE DURING ITS SLIGHT DISPLACEMENT WHILE AT THE SAME TIME PREVENTING ANY EXCESS HEAT LIABLE TO PARTLY VAPORIZE THE FUEL FROM BEING TRANSMITTED TO THE FUEL SUPPLY LINE. 